WIRELESS CORROSION SENSOR

• US 20080204275A1
• Filed: 02/07/2008
• Published: 08/28/2008
• Est. Priority Date: 02/09/2007
• Status: Active Grant

• Current Assignee: Luna Labs USA LLC
• Original Assignee: Luna Innovations, Inc.
• Inventors: Friedersdorf, Fritz J., Wavering, Thomas A., Bopp, Charles L.
• Granted Patent: US 8,085,165 B2
• Time in Patent Office: Days
• US Class Current: 340/870.16
• CPC Class Codes: G01N 17/04 Corrosion probes
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A passive sensor that is located on or adjacent to a structure that can be used to monitor the affect of environment on a structure or coating that is used to protect the structure. The sensor includes a parasitic element that interacts with the environment and influences the intensity of the electromagnetic response between the inductive element of the sensor and the antenna of the interrogation reader device. The condition of the parasitic element is determined by the radio frequency interaction of the reader antenna and the inductive element of the sensor. The parasitic element condition correlates to the environmental severity, or corrosivity of the environment and damage to metallic structures or protective coatings. An integrated circuit within the sensor is capable of storing identification, time, material, and measurement information. The sensor and system of the present invention is useful for tracking and monitoring cumulate environmental damage to a structure.

Claims

1. A sensor for sensing an affect of an environment on a structure on or near which the sensor is located, comprising:

a substrate;

an inductive element formed on a substrate for receiving electromagnetic radiation with a particular electromagnetic response;

a protective film that isolates the inductive element from the environment;

a parasitic element proximate to the inductive element and having a first affect on the electromagnetic response,

wherein as the environment interacts with and changes at least one characteristic of the parasitic element, the changed parasitic element has a second, different affect on the electromagnetic response that is detectable by a sensor reader to monitor changes to the structure.

2. The sensor in claim 1, wherein a difference between the first and second affects on the electromagnetic response corresponds to environmentally-induced changes to the structure.

3. The sensor in claim 1, wherein the change to the structure includes one or more of:

corrosion, erosion, exposure, physical or chemical change, a cumulative damage, or degradation of the structure or a protective coating on the structure.

4. The sensor in claim 1, wherein the parasitic element may be any geometry within, covering, or outside the inductive element that is in close proximity to but electrically insulated from the inductive element.

5. The sensor in claim 1, further comprising:

an integrated circuit connected to the inductive element enabling storage and communication of sensor information including one or more of;

identification, date/time stamp, material description, or prior sensor measurements,

wherein the integrated circuit is wirelessly powered by electromagnetic radiation received from the sensor reader via the inductive element.

6. The sensor in claim 1, further comprising:

a material separating the sensor from the structure including an electromagnetic absorber or magnetic material in proximity to the sensor for operation on metallic structures.

7. The sensor in claim 1, further comprising:

a coating on the parasitic element for monitoring a condition of a coating on the structure.

8. A sensing system comprising:

a sensor for sensing an affect of an environment on a structure on or near which the sensor is located, the sensor including;

a substrate,

an inductive element formed on a substrate for receiving electromagnetic radiation;

a protective film that isolates the inductive element from the environment;

a parasitic element proximate to the inductive element; and

an integrated circuit connected to the inductive element for enabling storage and communication of sensor information including one or more of;

identification, date/time stamp, material description, or prior sensor measurements, wherein the integrated circuit is wirelessly powered by electromagnetic radiation received from the sensor reader via the inductive element, and

a sensor reader including;

one or more antennas,

a transmitter, connected to the one or more antennas, for transmitting electromagnetic radiation that interacts with the sensor,

a receiver, connected to the one or more antennas, for detecting an amount of electromagnetic radiation provided by the sensor in response to the transmitted electromagnetic radiation, and

a processor for determining environmentally-induced change to the structure based on a change in the electromagnetic response caused by environmentally-induced changes to the parasitic element.

9. The system in claim 8, wherein the electromagnetic radiation between the sensor and the sensor reader is near field electromagnetic radiation communicated wirelessly.

10. The system in claim 8, wherein the electromagnetic radiation between the sensor and the sensor reader is far field electromagnetic radiation communicated wirelessly, wherein the sensor is configured to reflect back to the sensor reader a modulated version of the transmitted electromagnetic radiation.

11. The system in claim 8, where the inductive element is an antenna.

12. The system in claim 8, wherein the parasitic element is a conductor or dielectric that is in close proximity to but electrically insulated from the inductive element.

13. The system in claim 8, wherein the sensor is attached to a structure and changes to the parasitic element can be correlated to an environmentally-induced change to the structure.

14. The system in claim 8, wherein the environmentally-induced change to the structure includes one or more of the following characteristics:

corrosion, erosion, exposure, physical or chemical change, a cumulative damage, or degradation of the structure or a protective coating on the structure.

15. The system in claim 8, further comprising:

a reference element for measurement compensation,

wherein the reader is configured to receive another amount of electromagnetic radiation provided by the reference element in response to the transmitted electromagnetic radiation,

wherein the other amount of radiation is substantially unaffected by the parasitic element, and

wherein the processor is configured to reduce or eliminate one or more environmental factors other than the desired one or more characteristics.

16. The system in claim 15, wherein the processor is configured to differentiate between the inductive element and the reference element based on one or more of the following:

resonant frequency of the element, polarization of the element, phase of the element, differences in timing associated with the radiation received from the element, or differences in information modulated onto the radiation received from the element.

17. The system in claim 15, wherein the processor is configured to differentiate between the inductive element and the reference element based on differences in information modulated onto the radiation received from the element.

18. The system in claim 15, wherein the processor is configured to quantify an amplitude of the radiation received from each of the inductive element and the reference element.